In general, an electrolysis process is used for a variety of processes such as production or decomposition or precipitation and coating of a variety of chemical products. Such electrolysis processes accompany a reaction producing hydrogen gas mostly at the cathode in addition to an electrochemical reaction required in the electrolysis process. The hydrogen gas is renewable energy fuel source, and is produced as a by-product during the electrolysis process unless produced for additional purposes. However, such hydrogen gas has a very wide explosive range, thereby always has the inherent risk of explosion.
In order to exclude the risk of hydrogen gas explosion, a method of discharging hydrogen gas (H2) to the atmosphere after dilution with ambient air is mainly used in view of the fact that hydrogen gas is a very light gas. Further, processes that purify and recycle the hydrogen gas by increasing a purity of the hydrogen gas to upper limit of the explosive range and above have been adapted.
As an example of the electrolysis process, an electrolysis device using a technique, which is one of emerging techniques for sterilization and disinfection, of electrolyzing brine or seawater and producing an aqueous solution of sodium hypochlorite so as to be used as a disinfectant solution, has been developed.
In other words, the electrolysis device is a device that electrolyzes brine or seawater and generates sodium hypochlorite (Sodium Hypochlorite; NaOCl). Here, the produced sodium hypochlorite can be used in sterilization of purification plants, sewage treatment plants, and swimming pools, and processing a coolant of a power plant or ballast water of a vessel.
When operating the device generating sodium hypochlorite, the brine or seawater is electrolyzed in an electrolysis module, thereby generating chlorine, hydrogen, and oxygen gases. Here, the chlorine gas is quickly dissolved in water (H2O) or is reacted with hydroxide ions (OH−), and is converted to hypochlorite. After that, the hydrogen and oxygen gases that are not dissolved in water are discharged to the atmosphere through a gas-liquid separator. Here, the hydrogen gas is explosive when concentration thereof is equal to or greater than 4%. Thus, the hydrogen is discharged by using an air blower capable of forcibly supplying air, or the hydrogen is discharged after separation by the gas-liquid separator such as a cyclone separator, and dilution to concentration of less than 4%.
As such, the device generating sodium hypochlorite always possess the inherent risk due to hydrogen gas generation. Thus, it requires that the hydrogen gas be removed so as to prevent the underlying risk, thereby reducing the inherent risk due to hydrogen gas generation.